https://bugs.kde.org/show_bug.cgi?id=433857
Bug ID: 433857
Summary: Add validation to C++17 aligned new/delete alignment
size
Product: valgrind
Version: unspecified
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: memcheck
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
According to
https://en.cppreference.com/w/cpp/memory/new/operator_new
a) these operators should only be called when the alignment is greater than
__STDCPP_DEFAULT_NEW_ALIGNMENT__ (the contrary would either mean a compiler bug
or an explicit call to the operator with an alignment that it too small)
b) "The behavior is undefined if this is not a valid alignment value "
c) I suppose that the alignment size passed to new should match that passed to
delete.
For point b) the wording of the C++ 17 standard is
"6.6.5 Alignment
4 Alignments are represented as values of the type std::size_t. Valid
alignments include only those values
returned by an alignof expression for the fundamental types plus an additional
implementation-defined set
of values, which may be empty. Every alignment value shall be a non-negative
integral power of two."
For point b) I suggest just checking that the alignment is a power of 2.
Point c) looks more complicated, and I'll look at that another time.
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